1. Field of the Invention
This invention relates to methods and apparatus for cooling surfaces by evaporating a liquid refrigerant.
2. Introduction to the Invention
It is well known to produce a cooling effect by the evaporation of a liquid. A recent and particularly valuable therapeutic use of this effect is to provide localized freezing of a part of a human or animal body, e.g. in order to remove a wart or other growth. In this use, a refrigerant is maintained under pressure in a can and is dispensed, via a valve and an outlet tube, through a cotton wool bud which surrounds the discharge end of the outlet tube and which is placed on or near the site to be treated. Details of that method and of apparatus for use in that method are disclosed in U.S. Pat. No. 4,865,028 (Swart), the disclosure of which is incorporated herein by reference for all purposes.